CALGARY -- Calgary police are investigating a half dozen robberies that took place Monday and Tuesday in downtown Calgary.

In each case, the suspect approached a female victim, showed a knife and took the victim's cash, wallet or purse. Most of the robberies took place at LRT platforms along  Seventh Avenue, or on Eighth Avenue S.W. One took place in the Beltline, close to 12th Avenue and 11th Street S.W.

The suspect is described as a male of average height, with a slim build. He wore dark clothing, had his head covered and wore a mask or a red bandana across his face.

Each robbery took place between 2 p.m. and 10:30 p.m.

No one was injured.

Anyone with information is asked to contact the police at 403-266-1234. Anonymous tipsters can contact Calgary Crime Stoppers at 1-800-222-8477, online or by using the P3 Tips app available at Apple or the Google Play Store.